Today’s Moon Launch a Milestone for NASA

NASA's highly anticipated unmanned spacecraft to the moon - the first its kind in a decade for the United States, scheduled for liftoff at 5:12 p.m. Thursday from Cape Canaveral, Fla. - is the space agency's first step toward achieving its goal of sending humans back to the moon by 2020.

The hope is that, one day, astronauts will be able to stay and train there for extended periods.

The $504 million craft, the Lunar Reconnaissance Orbiter, is designed to identify safe landing sites and learn more about the moon's environment.

It will take the minivan-size orbiter about four days to reach the moon. It then will spend at least a year circling and taking photographs.

NASA had scheduled the orbiter's launch for Wednesday but postponed it a day because of launch conflicts with the space shuttle Endeavour. Wednesday's shuttle launch was delayed until July 11 because of a hydrogen-gas leak.

The orbiter is equipped with seven scientific instruments that can create detailed maps of the moon's surface as well as measure temperature and radiation.

A separate $79 million satellite attached to the orbiter is scheduled to smash into the moon's South Pole in early October and look for ice.

Previous missions have detected possible signs of ice, which could be used by future human outposts as drinking water or to make rocket fuel.

Two high-resolution cameras onboard can zero in on objects the size of a car. A third camera with a wide-angle lens will provide lower-resolution images in areas the size of a football field.

Scientists hope to photograph equipment left from the Apollo missions in the 1960s and early 1970s.

"We'll finally have the information about the moon that we already have about Mars," said Todd May, a NASA program manager.